Yoda does better with almost any group once you zeta his Battle Meditation. Can pretty much drop foresight on the whole team even if he don't have it right off the bat. But still Palps tends to hold onto teams better.

The Emperor is a lot more versatile. Yoda has Battle Meditation and foresight which make him annoying, but he needs a Jedi team to shine. Palpatine has a lot more utility and fits into way more team formations.

Yoda is a nice character to have, but in teams he is one of the characters that can be swapped out for others. EP works with a few different teams and whereas Yoda is limited to a Jedi team. EP also has abilities that debuff the an enemy team from the start and buffs his team. Also applies shock which is a couple of debuffs all in one.